Molecular cloning of a novel C or gamma type chemokine, SCM-1.

From human PBMC stimulated with PHA, we have isolated cDNA clones encoding a novel cytokine named SCM-1, which is significantly related to the CC and the CXC chemokines but has only the 2nd and the 4th of the four cysteines conserved in these proteins. Its gene is also distinctly mapped to human chromosome 1. SCM-1 is strongly induced in human PBMC and Jurkat T cells by PHA stimulation. Among various human tissues, SCM-1 is expressed most strongly in spleen. SCM-1 is found to be 60.5% identical to lymphotactin, a recently described murine lymphocyte-specific chemokine, which also retains only two cysteines. SCM-1 and lymphotactin may thus represent the human and murine prototypes of a novel C or gamma type chemokine family.